Upgrade to Hollowtech

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Xhrdgfsc
Posts: 3
Joined: 5 Feb 2023, 7:53pm

Upgrade to Hollowtech

Post by Xhrdgfsc »

I’m doing up my trusty 2012 Giant Defy and am considering going from square taper to hollowtech for a new Claris Crankset.

The current square taper is a BSA 68 x 110.5

I’m a bit confused about upgrading to Hollowtech - they all seem to be 1 size width as opposed to the square taper Bb’s.
I notice they only seem to come in 1 crank width giving a Q factor of 150.

The Shimano recommendation for Hollowtech is BB-RS501 but will any of the others fit? I want a black finish.

Is this an easy upgrade and does anyone have any advice that might help?

Cheers
mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: Upgrade to Hollowtech

Post by mattsccm »

What you'll get soon is a raft of comments saying that you are making a down grade not an upgrade. External BBs don't often last as long as a decent square taper which is why they are not liked by commuters, old timers, luddites, people who ride in "ordinary " clothes and many more. (only joking so don't bother complaining), long distance tourists and many more.
Your BB shell needs to be faced really and to be honest, with Claris you are hardly pushing into best quality stuff.
Either way you'll just need a 68mm job as the width is all in the chainset itself.
it is an easy job with the correct big spanner thingy. You must get the bearing preload on the left right!
pwa
Posts: 17366
Joined: 2 Oct 2011, 8:55pm

Re: Upgrade to Hollowtech

Post by pwa »

I'd start by asking whether the chainset you have in mind has the ring sizes you need. That is the main thing. The bottom bracket it uses is a secondary consideration.
Valbrona
Posts: 2694
Joined: 7 Feb 2011, 4:49pm

Re: Upgrade to Hollowtech

Post by Valbrona »

As per the first response ... Hollowtech road cups are just Hollowtech road cups. The width parameters are inherent in the crankset, so you get 'double' Hollowtech cranksets or 'triple' Hollowtech cranksets.
I should coco.
rareposter
Posts: 1988
Joined: 27 Aug 2014, 2:40pm

Re: Upgrade to Hollowtech

Post by rareposter »

The big advantage with Hollowtech is it does away with all the "what axle width do I need?" stuff, you just buy a Hollowtech BB. It's two sets of bearings that screw in, one each side.

The axle is integral to the chainset itself so it simply slides in, you pop the other crank arm on and tighten it all up. Dead simple.

Chainset can be any compatible system from Claris to Dura-Ace. The only major thing to consider is the adjustment of the front mech if you're altering chainring sizes dramatically.

As with all upgrades, make sure you clean everything up thoroughly before fitting the new BB and chainset.
BerlinMatt
Posts: 57
Joined: 2 Jan 2021, 9:16pm

Re: Upgrade to Hollowtech

Post by BerlinMatt »

That claris chainset is very heavy (although it works fine), some nicer chain rings for your existing cranks might be a better use of your money.
It is very quick to install, which is handy as they often wear out quickly :wink:
Being able to use any shimano bb is a good thing, although don't forget to add the spacers if using a mtb hollowtech.
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geomannie
Posts: 1093
Joined: 13 May 2009, 6:07pm

Re: Upgrade to Hollowtech

Post by geomannie »

pwa wrote: 5 Feb 2023, 9:17pm I'd start by asking whether the chainset you have in mind has the ring sizes you need. That is the main thing. The bottom bracket it uses is a secondary consideration.
+1 for the above. Also, if you do go Hollowtech, you have to learn to treat your BB as a consumable. You almost certainly will be replacing it quite often.
geomannie
Xhrdgfsc
Posts: 3
Joined: 5 Feb 2023, 7:53pm

Re: Upgrade to Hollowtech

Post by Xhrdgfsc »

Thanks, interesting answers!

So it would appear I’m probably just as well off sticking to square taper for now as I have a new SQ chain set ready to fit and a reasonably new BB.

Cheers!
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Upgrade to Hollowtech

Post by gregoryoftours »

Xhrdgfsc wrote: 5 Feb 2023, 8:21pm I’m doing up my trusty 2012 Giant Defy and am considering going from square taper to hollowtech for a new Claris Crankset.

The current square taper is a BSA 68 x 110.5

I’m a bit confused about upgrading to Hollowtech - they all seem to be 1 size width as opposed to the square taper Bb’s.
I notice they only seem to come in 1 crank width giving a Q factor of 150.

The Shimano recommendation for Hollowtech is BB-RS501 but will any of the others fit? I want a black finish.

Is this an easy upgrade and does anyone have any advice that might help?

Cheers
Yes nowt wrong with square taper, but if you do change to hollowtech the higher spec models of Shimano BB (the black ones that are a slightly smaller diameter to the BB-RS501) have lasted much, much longer (edit - than cheaper hollowtech BB) for me. Agree it's also important to get the BB shell of the frame faced for 2 piece cups external bottom brackets
Last edited by gregoryoftours on 7 Feb 2023, 9:08pm, edited 1 time in total.
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TrevA
Posts: 3551
Joined: 1 Jun 2007, 9:12pm
Location: Nottingham

Re: Upgrade to Hollowtech

Post by TrevA »

Hollow tech is supposed to be stiffer, as the BB diameter is bigger, but I have both square taper and Hollowtech on different bikes and I can’t say that I noticed any difference, even when sprinting for village signs! A Hollowtech BB bearing will last 3-4,000 miles, but a decent square taper BB should last 15-20,000 miles.
Last edited by TrevA on 9 Feb 2023, 4:13pm, edited 1 time in total.
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mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: Upgrade to Hollowtech

Post by mattsccm »

You might be able to feel more flex with a sqaure taper. I can't but I could see a 16 stone mates Camapg Record flex. When he swapped to a lower level through axle it didn't. However I would happily go back to square taper if I could find mid quality one and a nice sub-compact chainset to match.
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geomannie
Posts: 1093
Joined: 13 May 2009, 6:07pm

Re: Upgrade to Hollowtech

Post by geomannie »

mattsccm wrote: 7 Feb 2023, 4:46pm You might be able to feel more flex with a sqaure taper. I can't but I could see a 16 stone mates Camapg Record flex. When he swapped to a lower level through axle it didn't. However I would happily go back to square taper if I could find mid quality one and a nice sub-compact chainset to match.
Some ideas for better square taper BBs. I quite like the look of the Token, but have no experience of it.
https://www.restoration.bike/bikes-and- ... -brackets/
geomannie
Xhrdgfsc
Posts: 3
Joined: 5 Feb 2023, 7:53pm

Re: Upgrade to Hollowtech

Post by Xhrdgfsc »

My original sealed square bottom Bracket was by RPM and did approx 15k miles and was only replaced due to mileage.

Can recommend it!
gxaustin
Posts: 890
Joined: 23 Sep 2015, 12:07pm

Re: Upgrade to Hollowtech

Post by gxaustin »

Hollow tech is supposed to be stiffer, as the BB diameter is bigger, but I have both square taper and Hollowtech on different bikes and I can5 say that I noticed any difference, even when sprinting for village signs! A Hollowtech BB bearing will last 3-4,000 miles, but a decent square taper BB should last 15-20,000 miles.
I have a Hollowtech 2 push in BB. The original BB lasted 16,000 miles. The replacement has carried on for over 20,000 miles - is still going well.

I agree with another responder; the black, smaller diameter, Ultegra BB lasts better than the larger, silver Tiagra BB.
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